Firing chamber for caseless cartridge

ABSTRACT

A CASED CARTRIDGE FOR FIREARMS IN WHICH THE CARTRIDGE CASING IS EXPELLED THROUGH THE MUZZLE ALONG WITH THE PROJECTILE OR PROJECTILES TO PROVIDE THE ADVANTAGES OF CASE/ LESS AMMUNITION IN A CASED ROUND. A SYSTEM FOR CHAMBERING SUCH A CASED CARTRIDGE IS DISCLOSED, WHICH SYSTEM INCLUDES A BOLT ASSEMBLY HAVING A NOSE PORTION OF REDUCED DIAMTER. THE CARTRIDGE CASE IS FORMED FROM RESILIENT PLASTIC MATERIAL AND INCLUDES A REARWARDLY OPEN POCKET CONTAINING A PROPELLANT CHARGE AND A PRIMER. THE PRO-   PELLANT POCKET INCLUDES AN ANNULAR SKIRT PROJECTING BEYOND THE PROPELLANT CHARGE INTO WHICH SKIRT PROJECTS THE BOLT ASSEMBLY NOSE. THE BOLT ASSEMBLY NOSE INTERLOCKINGLY ENGAGE THE SKIRT TO PERMIT EXTRACTION OF AN UNFIRED ROUND, BUT DOES NOT HINDER EXPULSION OF THE CASING THROUGH THE MUZZLE IF THE ROUND IS FIRED. COOPERATING SHOULDERS ARE FORMED ON THE FIRING CHAMBER AND CASING TO POSITION THE CARTRIDGE FOR FIRING.

Nov. 9, 1971 w. B. WOODRING 3,618,246

FIRING CHAMBER FOR CASELESS CARTRIDGE Original Filed May 7. 1968 -1-YG-l INVENTOR I WILL/AM B. WOODR/NG I BY ATTORNEY United States Patent U.S. C]. 42-16 ll Claim ABSTRACT OF THE DISCLOS A cased cartridge for firearms in which the cartridge casing is expelled through the muzzle along with the projectile or projectiles to provide the advantages of caseless ammunition in a cased round. A system for chambering such a cased cartridge is disclosed, which system includes a bolt assembly having a nose portion of reduced diameter. The cartridge case is formed from resilient plastic material and includes a rearwardly open pocket containing a propellant charge and a primer. The propellant pocket includes an annular skirt projecting beyond the propellant charge into which skirt projects the bolt assembly nose. The bolt assembly nose interloc kingly engages the skirt to permit extraction of an unfired round, but does not hinder expulsion of the casing through the muzzle if the round is fired. Cooperating shoulders are formed on the firing chamber and casing to position the cartridge for firing.

This is a divisional application of my co-pending application Ser. No. 727,164, filed May 7, 1968.

This invention relates to ammunition and more particularly to shotshell type ammunition in which the entire round of ammunition including the casing, wads, projectiles, etc., is expelled through the muzzle of the firearm upon firing. A round of ammunition made in accordance with this invention eliminates the necessity of ejecting and extracting a spent case is as required with conventional shotshell type ammunition.

A conventional shotshell includes a tubular case formed from plastic or paper, a metallic head formed on one end of the casing and a closure formed at the opposite end, usually by infolding an end portion of the casing. The internal components comprise a charge of powder, one or more wad elements and a shot charge. A primer positioned in the head of the case ignites the propellant, which in turn fires the wadding and the shot charge down the barrel of a firearm. The empty fired case, retained in the chamber, is then extracted and ejected from the chamber and an unfired round is then loaded into the chamber for firing.

The present invention contemplates an entirely new ammunition concept wherein the casing, as well as all the other components of a shotshell, are expelled through the muzzle of a firearm when the cartridge is fired. This eliminates the necessity of ejecting and extracting the shotshell, thereby simplifying the function and number of component parts required in the firearm.

The ammunition of this invention combines the advantages of caseless ammunition systems, in which the entire cartridge is consumed upon firing, with many of the advantages of conventional cased ammunition. Ammunition of this invention is relatively durable and may be handled in substantially the same manner as a conventional cased shotshell. There is no fired casing remaining in the chamber after the ammunition of this invention is fired, thus the need to extract and eject a fired casing is obviated.

3,618,246 Patented Nov. 9, 1971 A major advantage attendant to the ammunition of this invention lies in the economic area. The ammunition of this invention can be produced at substantially lower cost than conventional cased shotshells. A factor contributing to the lower cost of the ammunition of this invention is the elimination therefrom of a metallic head portion found in conventional shotshells. Furthermore, the expendable casing of this invention can be economically manufactured by conventional means, such as injection molding of plastic. Special materials and processes to strengthen the casing by cold working and biaxial orientation are not required for the casing of this invention, while they are so required for conventional plastic shotshells. Thus it is contemplated that ammunition having superior quality can be offered to the average shooter at a substantially reduced cost.

It is, therefore, an object of this invention to provide a new type of ammunition which is economical to manufacture, is durable and can be readily handled and packaged, and has superior performance.

It is a further object of this invention to provide a cased shotshell for a firearm in which the entire shotshell, including the casing, is expelled through the muzzle upon firing, thereby eliminating the need for extracting and ejecting a spent cartridge casing.

It is yet another object of this invention to provide a new type of ammunition having a molded plastic casing which can be economically manufactured in conventional machinery by known processes.

These and other objects of this invention will be more fully disclosed in detail below with reference to the attached drawings in which:

FIG. 1 is a side view partially in section of a shotshell formed in accordance with this invention;

FIG. 2 is a side view partially in section of a modified embodiment of the shotshell of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a side view partially in section of a second modified embodiment of a shotshell formed in accord ance with this invention; and

FIG. 5 is a side sectional view of a portion of a firearm showing the shotshell of FIG. 4 seated in the firing chamber, and showing the engagement between the bolt and the shotshell.

Referring now to FIG. 1, a preferred embodiment of this invention is shown in the form of a shotshell. The shotshell includes a cylindrical casing, denoted generally by the numeral 2, formed preferably of injection molded polyethylene, or other flexible plastic material. The casing 2 is subdivided by an internal transverse web 4 into a forward facing cup portion 6 and a rearward facing cup portion 8. While the cup portions 6 and 8 are preferably formed as integral members, it is to be understood that the cups 6 and 8 can be formed as separate members which are subsequently joined together without departing from the spirit of this invention. The forward cup portion 6 serves to receive a pair of wads 10 disposed adjacent to the web 4 and a charge of shot pellets 12 adjacent to the wads 10. While a pair of wads 10 are shown in the forward cup 6, it is understood that the exact number of wads in the cartridge may be varied without departingfrom the spirit of this invention. Furthermore, the wads 16 may be entirely omitted from the forward cup 6 and may be compensated for by merely increasing the thickness of the transverse web 4 to provide additional cushioning for the shot charge. The forwardmost end of the cup portion 6 is closed by means of a cup 14 which overlies the shot charge 12. The cup 14 is preferably formed from polystyrene, polyethylene, paper, or some other relatively lightweight material. The

cup 14 is retained in place over the shot charge 12 by means of a cone crimp 16 formed at the upper edge of the cup portion 6, which cone crimp 16 slightly overlaps the edges of the cup .14. While a cup and an associated cone crimp are preferred for forming the closure of the shot containing cup 6, a disk of either frangible or non-frangible material may be used in place of the cup 14. Furthermore, it is contemplated that an integral closure in the form of a folded over crimp may be used to close the top of the forward cup 6.

The rearward cup portion 8 is operative to receive a compacted propellant pellet 18. The propellant pellet 18 may be adhesively secured to the inner wall of the cup portion 8, or it may be frictionally press fitted therein or retained by other suitable means. The propellant pellet 18 shown is of the impact ignition variety and includes a charge of primer material deposited in a recess 22 in the rear face of the pellet 18. While the pellet shown is of the impact ignition type, it is understood that propellant pellets ignitable by other known means may be utilized without departing for the spirit of this invention. The propellant pellet 18 is preferably formed from a compressed mass of slightly fibrous explosive, such as virgin nitrocellulose, or other compactible powder. The pellet may be formed by either wet or dry compaction methods. The rearward cup portion 8 preferably includes a skirt 24 operable to seal combustion gases after the cartridge has been fired and the inner surface of which provides for frictional engagement with the outer surface of a bolt assembly when chambered in a firearm. It is noted that the outside diameter of the forwardly facing cup portion 6 is smaller than the outside diameter of the rearwardly facing cup portion 8 with an oblique shoulder 26 being formed on the exterior of the casing 2 intermediate the outside surfaces of the respective cup portions 6 and 8. The shoulder 26 serves to seat the cartridge in a firing chamber of a shotgun and provides a surface on the cartridge operable to generate shot start after the propellant has been ignited.

The cartridge formed in accordance with this invention is preferably used with a full choke shotgun and operates in the following manner. The cartridge is inserted into the firing chamber of a firearm with the shoulder 26 being seated against a complementary shoulder or seat formed in the firing chamber. The bolt is then brought to the battery position and into frictional engagement with the inner urface of the skirt 24, and the propellant charge 18 is ignited. Initially after ignition of the propellant, the shoulder 26 bearing against the firing chamber seat resists forward movement of the cartridge until a predetermined gas pressure is reached. The resistance of the shoulder 26 is overcome and the entire cartridge, including the casing 2 is propelled through the barrel of the firearm. As the cartridge passes through the firearm barrel, the skirt 24 flexes outwardly to seal combustion gases, and the wall of the forward cup portion 6 prevents contact between the shot pellets 12 and the bore wall of the barrel. When the cartridge reaches the choke, the casing 2 is slowed by engagement therewith while the shot charge 12 passes out through the front end of the forward cup 6 dlslodging the cup 14 and deforming the cone crimp 16. The casing 2 continues through the choke and is expelled from the muzzle of the gun.

Referring now to FIGS. 2 and 3, a modified embodiment of the cartridge of FIG. 1 is shown. The modified cartridge includes a casing 2' having a forwardly facing cup portion 6' and a rearwardly facing cup portion 8'. The casing 2 is structurally identical to the casing 2, with the exception that the exterior surface of the rearward cup portion 8 includes a plurality of undercut areas, such as at 28, which are circumferentially spaced apart to define intermediate lugs 30 which extend forwardly from the front end of the outer surface of the cup 8'. The lugs 30 include forward oblique faces detfining shoulders 32 which are operative to engage a complementary shoulder or seat in the shotgun firing chamber. A comparison between the shoulder 26 on the casing 2, and the shoulders 32 on the casing 2 shows the latter to be of lesser total area, thereby providing less resistance to movement of the cartridge past the firing chamber seat after firing. Thus the cartridge embodiment shown in FIG. 2 will fire at a lower shot start value than the cartridge shown in FIG. 1. It is to be understood that while FIGS. 2 and 3 disclose three equal area lugs 32 equally spaced about the circumference of the cartridge casing 2', the size and spacing of the lugs may be varied to vary shot start without departing from the spirit of this invention.

Another modification of a cartridge formed in accordance with this invention is shown in FIG. 4. The cartridge of FIG. 4 includes a casing 2" having a forwardly opening cup portion '6" and a rearwardly opening cup portion 8". A transverse web portion 4" is interposed between the cups 6" and 8". A wad 10 and a shot charge 12" are disposed in the forward cup portion 6", with a disk member 15 serving to close the mouth of the forward cup portion 6". The disk 15 is retained in place by a cone crimp 16" formed at the upper edge of the cup wall. The rearwardly opening cup portion 8" includes a first flexible inwardly extending annular lip 34 formed on the inner surface of the cup 8" intermediate the ends thereof. A propellant pellet 18" is disposed in the cup 8" with the lip 34 overlapping the edge of the pellet 18 to retain the latter in the cup 8". It is readily apparent that the lip 34 must be sufficiently flexible to permit the pellet 18" to be inserted into the cup 8" without damaging the former, while at the same time being sufllciently rigid to retain the pellet 18" in the cup 8". A second inwardly extending lip 36 is formed at the rim of the cup 8" to provide means for engaging the bolt on a firearm, which means provides for a more positive engagement between the bolt and cartridge than does the previously noted frictional engagement between the bolt and the inner surface of the skirt, as will be set forth in more detail hereinafter. An oblique shoulder 26 is interposed between the outside surfaces of the forward cup 6" and the rearward cup 8". A generally forwardly extending flexible flange 38 is formed at the rearward edge of the shoulder 26 where the latter intersects the outer surface of the rearward cup 8". The flange 38 preferably extends around the entire periphery of the cup 8".

FIG. 5 shows the cartridge of FIG. 4 seated in a firearm and ready to be fired, and further shows the function of the lip 36 and flange 38. The shotgun, shown only fragmentarily, includes a barrel bore 40 and a bolt housing 42 which are open one to the other. An inwardly extending annular protrusion 44 is interposed between the bolt housing 42 and the barrel bore 40, to define a firing chamber area, the protrusion 44 including an oblique face 46 providing a complementary seat for the shoulders 26 or 32, or for the flange 38 on the various embodiments of the cartridge of this invention. A bolt assembly 48 is disposed in the housing 42 and is shown in the battery position. The bolt assembly 48 includes a head portion 50 of reduced diameter which telescopes into the open end of the cup 8" on the cartridge. A groove 52 is formed on the outside surface of the bolt head 50, the groove 52 providing a recess into which the cartridge lip 36 is received as the head 50 moves into the cartridge cup 8". The lip 36 and groove 52 provide a positive connection between the bolt assembly 48 and the cartridge casing 2" whereby the latter may be extracted from the firing position should one desire to unload a loaded gun, or should a misfire occur. It is noted that the lip 36 must be sufficiently flexible to release from the groove 52 when the cartridge is fired, but sufficiently rigid to remain in the groove 52 when the bolt assembly 48 is moved to its retired position should the cartridge not be fired.

As shown in FIG. 5, when the cartridge is placed in its firing position and the bolt assembly 48 is moved to its battery position, the flange 38 is moved against the seat 46 in the firing chamber. By providing a flexible flange 38 which can be deflected or crushed against the seat 46 as the bolt assembly 43 moves to its battery position, the propellant pellet 18 is protected against excessive and possibly damaging pressure which could otherwise be directed against it by the front face of the bolt assembly 48. Thus, the flange 38 provides a flexible shoulder for seating in the firing chamber, rather than a rigid one.

When the firing pin 54 is caused to strike the primer 20", the propellant 18" is ignited producing high pressure gases. The gases are sealed by gas grooves 56 formed in the bolt assembly, and when the gas pressure reaches a predetermined level, shot start is initiated, the rearward cup 8" is driven past the protrusion 44, and the entire cartridge is driven through the barrel bore 40.

It is thus readily apparent that this invention provides cased ammunition which, when fired from a firearm, leaves no casing in the firearm to be extracted and ejected. Furthermore, shotshell ammunition of substantially reduced cost can be produced in accordance with this invention while sacrificing substantially none of the durability and quality of conventional shotshells.

Although reference has been made to a particular embodiment of the present invention, various modifications will readily suggest themselves to those skilled in the art and reference should be made to the appended claim to determine the scope of the invention.

What is claimed is:

1. A system for firing an expendable cartridge, said system comprising:

(a) means forming a firing chamber, said firing chamber having an inwardly and forwardly tapered shoulder disposed therein;

(b) bolt means mounted rearwardly of said firing chamber, said bolt means including a projecting nose portion operable to project into said firing chamber when said bolt means is in a battery position;

(c) a cartridge in said firing chamber, said cartridge including a casing of resilient plastic material, said casing having complementary shoulder means disposed in substantially face-to-face relation to said firing chamber shoulder to position said cartridge in said firing chamber, and said casing including a rearwardly extending annular skirt portion telescopingly arranged with respect to said bolt means nose; and

(d) extractor means including rib means formed on one of said bolt nose means and said cartridge skirt means, and groove means formed on the other of said bolt nose means and said. cartridge skirt means, said rib means and said groove means being disposed in interlocking relationship to provide for extraction of an unfired cartridge from said firing chamber when said bolt means is move-d out of said chamber, and, by reason of the resiliency of said casing, said interlocking relationship being disrupted when said cartridge is fired from said firing chamber to permit the entire cartridge to be expelled from said firing chamber.

References Cited UNITED STATES PATENTS 3,166,864 1/1965 Scanlon, Jr 42-16 3,501,858 3/1970 Hensley et al. 4216 3,485,170 12/1969 Scanlon 102 -38 3,060,855 10/1962 Henning et al 102-38 3,144,727 8/ 1964 De Caro et al. 42-25 FOREIGN PATENTS 7,076 5/ 1890 Great Britain 102-38 BENJAMIN A. BORCHELT, Primary Examiner C. T. JORDAN, Assistant Examiner US. Cl. X.R.

42- 25, 76 R; 102-42 R, 43 P 

